The mercury linear ion trap frequency standards (LITS) at NASA Jet Propulsion Laboratory have been demonstrated with applications in NASA deep space missions. In particular, the long-term stability and practicality of the ground-based clock LITS9 have attracted significant interest for ground-based time-keeping and metrology. However, the mercury radio frequency (RF) discharge lamp and the associated optical design used in these clocks for optical pumping and detection may limit the short-term stability of the clock, which consequently constrains use in broader applications, such as global navigation satellite systems, time and frequency metrology, academic pursuits studying the fundamental laws of physics, etc.
An increase of vacuum ultraviolet (VUV) light output from the plasma discharge lamp light source used in trapped ion clock atomic state preparation and detection should improve the clock signal-to-noise ratio (SNR) and decrease optical pumping times. Both lead to an improvement in short-term clock stability and/or enable the use of a local oscillator having lower cost and improved performance. Accordingly, an improved lamp that increases SNR and decreases optical pumping times may be beneficial.